Tags: sgrassie/BlogHelper9000

Add rebase_series bulk reschedule for slipped series (#163)

ScheduleService.RebaseSeries moves a series' first unpublished dated
entry to a new start date (defaulting to the next occurrence of the
series' weekday strictly after today) and shifts every other
unpublished dated entry by the same delta, preserving spacing;
ShiftSeries is the plain days-delta variant. Both run as a single
atomic UPDATE and never touch published or undated entries.

Exposed as the rebase_series MCP tool (newStartDate | days | weeks)
and the schedule-rebase CLI command (--start | --days | --weeks).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>